The objectives of this study are to compare sensory scales developed in a simple magnitude estimation experiment of individual stimuli with a more complex magnitude estimation experiment which requires comparative judgments of relations between stimulus pairs. Subjects make numerical judgments of sensations associated with electrical tooth pulp stimulation. In one case, they estimate the difference between two sensations induced by stimulation of two different incisor teeth; in the other, they estimate the magnitude of sensations induced by stimulation of one incisor. The difference judgments were analyzed by Conjoint Measurement analysis; a scaling technique which tests for underlying additive structure before determining the sensory scales. In the magnitude estimation experiment of individual stimuli, the geometric mean responses for each current level are assumed to be ratio scales of sensory magnitude. Single-stimulus estimates reliably followed Stevens' power function law with an exponent greater than one, as is common with electrical stimulation of skin. Difference estimates seemed to be based on shallower psychophysical functions than those derived from the single-stimulus estimates, consistent with results from other perceptual continua.